Improve error message on : invalid use

Author: mariocj89

Lib/_strptime.py

@@ -462,7 +462,8 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
                     z = z[:3] + z[4:]
                     if len(z) > 5:
                         if z[5] != ':':
-                            raise ValueError(f"Unconsistent use of :")
+                            msg = f"Unconsistent use of : in {found_dict['z']}"
+                            raise ValueError(msg)
                         z = z[:5] + z[6:]
                 hours = int(z[1:3])
                 minutes = int(z[3:5])

Lib/test/test_strptime.py

@@ -349,8 +349,9 @@ def test_bad_offset(self):
             _strptime._strptime("-01:30:30.1234567", "%z")
         with self.assertRaises(ValueError):
             _strptime._strptime("-01:30:30:123456", "%z")
-        with self.assertRaises(ValueError):
+        with self.assertRaises(ValueError) as err:
             _strptime._strptime("-01:3030", "%z")
+        self.assertEqual("Unconsistent use of : in -01:3030", str(err.exception))
 
     def test_timezone(self):
         # Test timezone directives.